EV chargers, Article 220.83, Article 310.12, another residential idiot arguing with the AHJ!

[Elect117]

By applying the EVSE charger with a demand factor of 40% then you will end up overloading the service in no time. Lets say our magic number is enough VA to load up to 199A, so 47,760VA.

Lets start with Example D2(b) - we will add one 48*240=11,520

So the new total general load is 44,320.

10,000+(.4*34,320) (and then the AC from the example) so 23,728+10,080 = 33,808VA

We are less and if we do it the way I was suggesting, 29200VA (from example)+(11520*1.25) = 43600VA. Still good.

Lets add two chargers, new general load is 55,840VA, --> 38,416VA. I would say we are at risk of overloading the service, but lets continue until the optional method agrees.

3 chargers --> 43,024

4 chargers --> 47,632 (198.5A)

So 4 chargers is probably the most we are going to get.

4 chargers at full load, running continuously, at the same time, is a full load current of 192A and if you factor in the continuous load, you will be over 200.

Based on the optional method you are okay with 4 chargers and 310.12' reduction to have the lights, chargers, AC units, etc. running and be okay.

Based on good judgement, you are setting them up to trip their breaker or worse.

 

[tortuga]

(A) Since Chapter 6 is permitted to amend Chapter 4, and 422.31 and 625.43 are addressing the same question (disconnects), 625.43 takes precedence over 422.31.

625.43 only addresses equipment more than 60 amps or 150 volts to ground, it does not modify 422.31

(B) An EVSE is not an appliance or utilization equipment.

Right and I think his inspector is saying we can't include it as one in 220.83 (A)(3)

 

[Elect117]

625.43 only addresses equipment more than 60 amps or 150 volts to ground, it does not modify 422.31

Right and I think his inspector is saying we can't include it as one in 220.83 (A)(3)

625 addresses EVSE equipment and supersedes the 400s. Mainly when a section addressing disconnects within in it, like transformers and motors, should be followed and modifies the more general sections like 422.

 

[wwhitney]

625.43 only addresses equipment more than 60 amps or 150 volts to ground, it does not modify 422.31

It's a general legal principle that a requirement like 625.43 that says "some specific Xs must do Y" also means "all other Xs do not need to do Y." It even has a fancy Latin name if you want to look it up.

So 625.43 is telling us that EVSEs that are not "more than 60A or 150V to ground" do not need a disconnect. This would override 422.31 if that section applied.

Right and I think his inspector is saying we can't include it as one in 220.83 (A)(3)

I'd say the EV is an appliance located to be used on a specific circuit, the circuit with the EVSE.

Cheers, Wayne

 

[wwhitney]

By applying the EVSE charger with a demand factor of 40% then you will end up overloading the service in no time.

Yes, if you want to install an unlikely number EVSEs. Your post nicely spells out what I said in post #7. For 1 or 2 EVSEs, there's not really a problem. Proposals to install 3 or more EVSEs under 220.82 deserve extra scrutiny or discouragement, but I don't think the NEC provides the AHJ the necessary tools to deny such a request.

Cheers, Wayne

 

[ramsy]

Sorry, but no. We were discussing 220.14, not 220.12. Also the section you cite refers to 'general lighting and general use receptacles' which an EV is not.

Annex D calls out other articles to determine loads, and the examples specifically adopt 220 part II & III, to determine if loads may be subject to demand factors.

Without a demand factor specified by part II or III, example D4(b) shows part IV wont allow it.

Mechanical interlocks, and load shedding controls are load factors approved by AHJ's during EVSE installation.

 

[tortuga]

It's a general legal principle that a requirement like 625.43 that says "some specific Xs must do Y" also means "all other Xs do not need to do Y." It even has a fancy Latin name if you want to look it up.

So 625.43 is telling us that EVSEs that are not "more than 60A or 150V to ground" do not need a disconnect. This would override 422.31 if that section applied.

I dont buy that, but since we agree an EVSE is not an appliance its moot?

I'd say the EV is an appliance located to be used on a specific circuit, the circuit with the EVSE.

Its not a fixed appliance

 

[wwhitney]

Without a demand factor specified by part II or III, example D4(b) shows part IV wont allow it.

What are you trying to say here? I don't see anything in example D4(b) that is relevant to this discussion.

FWIW, the individual apartment load in example D(4)(b) could have been calculated via 220.82, while still using 220.84 for the 20 or 40 unit feeder loads.

Cheers, Wayne

 

[wwhitney]

Its not a fixed appliance

So? The language in 220.82(B)(3)(a) is "All appliances that are fastened in place, permanently connected, or located to be on a specific circuit." The EV is located to be on a specific circuit, it doesn't have to be "fixed."

Cheers, Wayne

 

[tortuga]

The EV is located to be on a specific circuit, it doesn't have to be "fixed."

Not really, if I have a hard wired EVSE on my garage but have my van parked there to work on it for the weekend my wife might just use her Level 1 charger on a cord, so the appliance (the vehicle charger in the car) is not located to be on a specific circuit. And even then were now calling a electric car an appliance.

Proposals to install 3 or more EVSEs under 220.82 deserve extra scrutiny or discouragement

Clearly the optional calc goess off the rails with EVSE @ 40%, and I could easily have three or more EVSE's at a large home, I think the OP's AHJ made a determination that you can't use any optional calcs with an EVSE. The AHJ does not want to chance it case by case. The 220 optionals need updating and sooner than 2026.

 

[wwhitney]

Not really, if I ahve a hard wired EVSE on my garage but have my van parked there to work on it for the weekend my wife might just use her Level 1 charger on a cord, so the appliance (the vehicle charger) is not located to be on a specific circuit.

The validity of that argument strikes me as on par with "what if I plug my microwave oven into a bedroom receptacle, so shouldn't we count the bedroom circuit as an SABC?" It's just not a sufficiently realistic scenario to consider when applying the NEC.

Particularly as the result of not being covered in 220.82(B) or 220.82(C) is that the load doesn't enter into the calculation at all, not that we are disqualified from using 220.82. To wit, 220.82(A) says "The calculated load shall be the result of adding the loads from 220.82(B) and (C)." End of calculation.

Cheers, Wayne

 

[tortuga]

The validity of that argument strikes me as on par with "what if I plug my microwave oven into a bedroom receptacle, so shouldn't we count the bedroom circuit as an SABC?" It's just not a sufficiently realistic scenario to consider when applying the NEC.

I mean if I drove my microwave to work every day ...
The CMP never considered an EVSE when the optional calcs were written and a EVSE is not an appliance. Arguably an electric car is not an appliance. The same issue could be had with an RV receptacle on a dwelling.

 

[ramsy]

What are you trying to say here? I don't see anything in example D4(b) that is relevant to this discussion.

The example uses 6kVA electric heat, and 2.5kVA water heater, without any extra demand factor added by part IV.

Don't believe part IV allows a demand factor for EVSE loads, without a part II & III demand factor.

 

[wwhitney]

The example uses 6kVA electric heat, and 2.5kVA water heater, without any extra demand factor added by part IV.

For the single unit feeder, the example decided to do the calculation via Part III. It could have been done by 220.82 (part IV) instead, and then there would be demand factors on (some of) the above.

For the multiple unit feeder, the example applies the 220.84 demand factors at the end.

So no, the fact that example D4(b) chose to use Part III for the single unit feeder rather than Part IV doesn't mean that you can't use Part IV for the single unit feeder, and has no bearing on this discussion.

Cheers, Wayne

 

[ramsy]

For the single unit feeder, the example decided to do the calculation via Part III. It could have been done by 220.82 (part IV) instead, and then there would be demand factors on (some of) the above.

For the multiple unit feeder, the example applies the 220.84 demand factors at the end.

So no, the fact that example D4(b) chose to use Part III for the single unit feeder rather than Part IV doesn't mean that you can't use Part IV for the single unit feeder, and has no bearing on this discussion.

Thank you. The bearing is me learning makes good discussion.

 

[tortuga]

The example uses 6kVA electric heat, and 2.5kVA water heater, without any extra demand factor added by part IV.

Don't believe part IV allows a demand factor for EVSE loads, without a part II & III demand factor.

What do you mean by part II & III demand factor?

 

[jaggedben]

Do you consider an EVSE to be an appliance?

No. (If there's an appliance in the circuit, it would be the EV.)

If not then
can we use 220.83(A) if you have loads that don't fit in (A)(1)-(A)(3) ?

It doesn't say you can't. It just says which loads are required to be included in the calc.

Clearly this was not intended, but it just highlights that Article 220 needs to address EV charging clearly and directly if we want to avoid these uncertainties.

If an EVSE is an appliance then do we need a disconnect within sight of it? 422.31

See above. This, along with various other code references to appliances that aren't appropriate for EV charging, is certainly a reason I'm not in favor of EVSE's being considered appliances.

 

[jaggedben]

In a contest between "strong logic" and "practical details that make application difficult" I will pick the strong logic every time.

And I'll pick the practical application everytime, meaning whatever I think is safe and the AHJ will also accept. I actually have to get this work done, after all.

Well, they don't include any EVSEs, do they? They all predate the introduction of EVSEs. So that has little bearing on the current question.

Some of them include air-conditioning loads which would be continuous, and simply use the amp ratings.

 

[wwhitney]

Some of them include air-conditioning loads which would be continuous, and simply use the amp ratings.

Are you saying all A/C loads are continuous? I disagree. Even when running full blast, the operating current will only match the nameplate current under a particular combination of indoor and outdoor temperatures. I don't think it would be "expected" for those conditions to last for over 3 hours.

Cheers, Wayne

 

[jaggedben]

I am sorry. I misread what you said. I thought you were saying part 2 doesn't apply to part 4. Like in a general way.

I was pointing out that Part IV doesn't say anything about including all the loads mentioned in part II. Which is true.

From NEC 2020,
"
220.40 General.
The calculated load of a feeder or service shall not be less than the sum of the loads on the branch circuits supplied, as determined by Part II of this article, after any applicable demand factors permitted by Part III or IV or required by Part V have been applied.

Okay. This does seem to suggest that you can't leave the EV load out of a Part IV calculation, even though some Part IV methods don't clearly include it in their lists of what loads must be included.

This requirement is in an odd spot being at the beginning of Part III rather than at the beginning of the whole article. One can read Parts I and IV and think that one is permitted to do a load calc as described in Part IV without looking at Parts III or II (except as referenced.)

I mean, I have never performed a load calc where I left out the EV charger, or counted it at 180VA. I'm just being devil's advocate and pointing out how much of a gap there is in how the present code treats this.